Farm tire designs for industrial service are classified as R-4 service. Overall R-4 service is quite severe and typically involves high loads at a large degree of reading. The vehicles to which the tires are mounted typically are exposed to large amounts of debris, hard packed soil conditions and high load service conditions.
Often times the vehicle has a back hoe bucket or a front skid loader attached to the vehicle. The tires must traverse gravel and broken concrete and hard packed dirt normally. Occasionally the work site can get rain soaked requiring good traction in wet soil conditions.
These tires are generally relatively small and typically have a nominal rim diameter of 28" (71 cm) or less. They generally have a nonskid depth at the centerline of the tire at approximately 1" (2.54 cm). A typical tire may be a 400/70R24 tire. This tire when produced in a radial construction will have a carcass with 3 to 4 plies of synthetic cord reinforcement. The cords generally are nylon or polyester. The carcass will further include four belts of high flex polyester, nylon or aramid. Historically, these tires have been all fabric reinforced in order to provide better ride and handling.
There has been a continual tradeoff in attempting to increase the aggressive offroad and tractor performance of these tires while maintaining the treadwear durability and ride requirements. The invention disclosed in this patent application teaches a novel tread that is both comfortable riding, long wearing while also achieving superior offroad traction in both the forward and reverse direction of vehicle travel.